A woman was seriously injured when a car and caravan rolled over on Indian Ocean Drive this afternoon.

The accident happened about 1.45pm about two kilometres south of Knobby Head, between Leeman and Arrowsmith.

A St John Ambulance spokesman said the woman suffered a serious abdominal injury.

She was taken to Jurien Bay hospital where the RAC rescue chopper was to take her to Royal Perth Hospital.

A police spokeswoman said the other occupants in the car, including several children, were believed to have suffered minor injuries.